3245 may penetrate the gate stack structure 3210. Each of the semiconductor chips 2200 may further include the input/output pad 2210 (see FIG. 1B).

Referring to FIG. 1D, in a semiconductor package 2003A, each of semiconductor chips 2200b may include a semiconductor substrate 4010, a first structure 4100 on the semiconductor substrate 4010, and a second structure 4200 disposed on the first structure 4100 and bonded to the first structure 4100 by a wafer bonding method.

The first structure 4100 may include a peripheral circuit region including peripheral interconnection lines 4110 and first bonding structures 4150. The second structure 4200 may include a common source line 4205, a gate stack structure 4210 between the common source line 4205 and the first structure 4100, memory channel structures 4220 penetrating the gate stack structure 4210, bit lines 4240 electrically connected to the memory channel structures 4220, gate contact plugs 4235 electrically connected to word lines WL (see FIG. 1A) of the gate stack structure 4210, respectively, and second bonding structures 4250. For example, the second bonding structures 4250 may be electrically connected to the memory channel structures 4220 through the bit lines 4240 electrically connected to the memory channel structures 4220. The first bonding structures 4150 of the first structure 4100 may be bonded to the second bonding structures 4250 of the second structure 4200. For example, bonded portions of the first bonding structures 4150 and the second bonding structures 4250 may be formed of copper (Cu). Each of the semiconductor chips 2200b may further include the input/output pad 2210 (see FIG. 1B).

In some embodiments, the semiconductor chips 2200 of FIG. 1C or the semiconductor chips 2200b of FIG. 1D may be electrically connected to each other through the connection structures 2400 (see FIG. 1B) having the bonding wire shapes. In some embodiments, semiconductor chips (e.g., the semiconductor chips 2200 of FIG. 1C or the semiconductor chips 2200b of FIG. 1D) in a single semiconductor package may be electrically connected to each other through connection structures including through-silicon vias (TSV).

FIG. 2A is a plan view illustrating a semiconductor device according to some embodiments. FIG. 2B is a cross-sectional view taken along a line A1-A1′ of FIG. 2A. FIG. 2C is an enlarged view of a region ‘B1’ of FIG. 2A. FIG. 2D is a cross-sectional view taken along lines C1-C1′, D1-D1′ and E1-E1′ of FIG. 2C.

Referring to FIGS. 2A and 2B, a semiconductor device may include a peripheral circuit structure PST and a memory cell structure CST on the peripheral circuit structure PST.

The peripheral circuit structure PST may include a substrate 100. The substrate 100 may have a plate shape extending along a plane defined by a first direction D1 and a second direction D2. The first direction D1 and the second direction D2 may intersect each other. For example, the first direction D1 and the second direction D2 may be horizontal directions perpendicular to each other. In some embodiments, the substrate 100 may be a semiconductor substrate. For example, in some embodiments, the substrate 100 may include silicon, germanium, silicon-germanium, GaP, or GaAs. In some embodiments, the substrate 100 may be a silicon-on-insulator (SDI) substrate or a germanium-on-insulator (GOI) substrate.

The peripheral circuit structure PST may include a peripheral circuit insulating layer 110 on the substrate 100. The peripheral circuit insulating layer 110 may include an insulating material. For example, the peripheral circuit insulating layer 110 may include an oxide. In some embodiments, the peripheral circuit insulating layer 110 may be a multi-layered insulating layer.

The peripheral circuit structure PST may further include a peripheral transistor 101. The peripheral transistor 101 may be provided between the substrate 100 and the peripheral circuit insulating layer 110. In some embodiments, the peripheral transistor 101 may include source/drain regions, a gate electrode, and a gate insulating layer. Device isolation layers 103 may be provided in the substrate 100. The peripheral transistor 101 may be disposed between the device isolation layers 103. The device isolation layer 103 may include an insulating material.

The peripheral circuit structure PST may further include peripheral contacts 105 and peripheral conductive lines 107. The peripheral contact 105 may be connected to the peripheral transistor 101 and/or the peripheral conductive line 107, and the peripheral conductive line 107 may be connected to the peripheral contact 105. The peripheral contact 105 and the peripheral conductive line 107 may be provided in the peripheral circuit insulating layer 110. The peripheral contact 105 and the peripheral conductive line 107 may include a conductive material.

The memory cell structure CST may include a source structure SST, a first gate stack structure GST1, a second gate stack structure GST2, first memory channel structures CS1, second memory channel structures CS2, third memory channel structures CS3, dummy channel structures DCS, a connection structure 200, a first separation structure 151, and a second separation structure 152.

The source structure SST may include a first source layer SL1 on the peripheral circuit structure PST, a second source layer SL2 on the first source layer SL1, and a third source layer SL3 on the second source layer SL2.

The first to third source layers SL1, SL2 and SL3 may include a conductive material. For example, the first to third source layers SL1, SL2 and SL3 may include poly-silicon. The second source layer SL2 may be a common source line.

The first gate stack structure GST1 may be provided on the source structure SST. The first gate stack structure GST1 may include insulating patterns IP and conductive patterns CP, which are alternately stacked in a third direction D3. The third direction D3 may intersect the first direction D1 and the second direction D2. For example, the third direction D3 may be a vertical direction perpendicular to the first direction D1 and the second direction D2.

The second gate stack structure GST2 may be provided on the first gate stack structure GST1. The second gate stack structure GST2 may include insulating patterns IP and conductive patterns CP, which are alternately stacked in the third direction D3.

The insulating patterns IP may include an insulating material. For example, the insulating patterns IP may include an oxide. The conductive patterns CP may include a conductive material. For example, the conductive patterns CP may include tungsten.

The number of the gate stack structures GST1 and GST2 is not limited to FIG. 2B. In some embodiments, the number of the gate stack structures GST1 and GST2 may be 3 or more.

The numbers of the insulating patterns IP and the conductive patterns CP in the first gate stack structure GST1 and the numbers of the insulating patterns IP and the conductive patterns CP in the second gate stack structure GST2 are not limited to those illustrated in FIG. 2B.

The first memory channel structures CS1, the second memory channel structures CS2, the third memory channel structures CS3 and the dummy channel structures DCS may extend in the third direction D3 to penetrate the insulating patterns IP and the conductive patterns CP of the first gate stack structure GST1, the insulating patterns IP and the conductive patterns CP of the second gate stack structure GST2, and the third source layer SL3 and the second source layer SL2 of the source structure SST.

Each of the first memory channel structures CS1, the second memory channel structures CS2, the third memory channel structures CS3 and the dummy channel structures DCS may include an insulating capping layer 189, a channel layer 187 surrounding the insulating capping layer 189, and a memory layer 183 surrounding the channel layer 187. It is noted that, in FIG. 2B, the insulating capping layer 189, the channel layer 187, and the memory layer 183 are illustrated with respect to the first memory channel structures CS1. However, the second memory channel structures CS2, the third memory channel structures CS3 and the dummy channel structures DCS have similar structures to the first memory channel structures CS1, and thus repeated description thereof is omitted for conciseness.

The insulating capping layer 189 may include an insulating material. For example, the insulating capping layer 189 may include an oxide. The channel layer 187 may include a conductive material. For example, the channel layer 187 may include poly-silicon. The channel layer 187 may be electrically connected to the second source layer SL2. The second source layer SL2 may penetrate the memory layer 183 so as to be connected to the channel layer 187.

The memory layer 183 may be capable of storing data. In some embodiments, the memory layer 183 may include a tunnel insulating layer surrounding the channel layer 187, a data storing layer surrounding the tunnel insulating layer, and a blocking layer surrounding the data storing layer.

Each of the first memory channel structures CS1, the second memory channel structures CS2, the third memory channel structures CS3 and the dummy channel structures DCS may further include a bit line pad 185 provided on the channel layer 187. The bit line pad 185 may include a conductive material. For example, the bit line pad 185 may include poly-silicon or a metal.

The first and second separation structures 151 and 152 may extend in the third direction D3 to penetrate the first and second gate stack structures GST1 and GST2. The first and second separation structures 151 and 152 may extend in the second direction D2. The first and second separation structures 151 and 152 may be spaced apart from each other in the first direction D1. The first and second separation structures 151 and 152 may be separation structures adjacent to each other. The first and second separation structures 151 and 152 may include an insulating material. In some embodiments, the first and second separation structures 151 and 152 may further include a conductive material in the insulating material.

The first memory channel structures CS1, the second memory channel structures CS2, the third memory channel structures CS3 and the dummy channel structures DCS may be disposed between the first separation structure 151 and the second separation structure 152.

A distance between the first memory channel structure CS1 and the dummy channel structure DCS may be greater than a distance between the second memory channel structure CS2 and the dummy channel structure DCS. The distance between the second memory channel structure CS2 and the dummy channel structure DCS may be greater than a distance between the third memory channel structure CS3 and the dummy channel structure DCS.

The arrangement of the first to third memory channel structures CS1, CS2 and CS3 is not limited to the arrangement illustrated in FIGS. 2A and 2B. In some embodiments, the distance between the first memory channel structure CS1 and the dummy channel structure DCS may be less than the distance between the second memory channel structure CS2 and the dummy channel structure DCS, and the distance between the second memory channel structure CS2 and the dummy channel structure DCS may be less than the distance between the third memory channel structure CS3 and the dummy channel structure DCS.

Referring to FIGS. 2A, 2B, 2C and 2D, the connection structure 200 may include a first insulating layer 201, a second insulating layer 203 on the first insulating layer 201, a third insulating layer 205 on the second insulating layer 203, a fourth insulating layer 207 on the third insulating layer 205, a fifth insulating layer 209 on the fourth insulating layer 207, a sixth insulating layer 211 on the fifth insulating layer 209, a seventh insulating layer 213 on the sixth insulating layer 211, stud contacts 221 penetrating the first and second insulating layers 201 and 203, first contacts CT1 and second contacts CT2 which penetrate the third insulating layer 205, first bit lines BL1 in the fourth insulating layer 207, third contacts CT3 and bypass structures BP which penetrate the fourth and fifth insulating layers 207 and 209, fourth contacts CT4 and fifth contacts CT5 which penetrate the sixth insulating layer 211, and second bit lines BL2 and third bit lines BL3 in the seventh insulating layer 213. Each of the memory channel structures CS1, CS2 and CS3 may overlap with the first to third bit lines BL1, BL2 and BL3 in the third direction D3. The first to third bit lines BL1, BL2 and BL3 may extend in the first direction D1. The first and third bit lines BL1 and BL3 may be alternately arranged in the second direction D2 when viewed in a plan view. The second and third bit lines BL2 and BL3 may be alternately arranged in the second direction D2. Each of the first bit line BL1, the second bit line BL2 and the third bit line BL3 may overlap with the first to third memory channel structures CS1, CS2 and CS3, arranged in the first direction D1, in the third direction D3.

The first to seventh insulating layers 201, 203, 205, 207, 209, 211 and 213 may include an insulating material. For example, the first to seventh insulating layers 201, 203, 205, 207, 209, 211 and 213 may include an oxide.

Each of the stud contacts 221 may be connected to the first memory channel structure CS1, the second memory channel structure CS2 or the third memory channel structure CS3. The stud contact 221 may include a conductive material.

Each of the first contact CT1 and the second contact CT2 may be connected to the stud contact 221. The first contact CT1 and the second contact CT2 may be located at the same level. Top surfaces of the first contact CT1 and the second contact CT2 may be coplanar with each other. The first contact CT1 may overlap with the first bit line BL1 and the second bit line BL2 in the third direction D3. The second contact CT2 may overlap with the third bit line BL3 in the third direction D3. The first contact CT1 may be connected to the first bit line BL1. The first contact CT1 may be electrically connected to the first memory channel structure CS1. The second contact CT2 may be electrically connected to the second memory channel structure CS2 or the third memory channel structure CS3. The first and second contacts CT1 and CT2 may include a conductive material.

The first bit line BL1 may be electrically connected to the first memory channel structure CS1 through the first contact CT1 and a corresponding one of the stud contacts 221. The first bit line BL1 may be electrically isolated from the second memory channel structure CS2 and the third memory channel structure CS3. The first bit line BL1 may overlap with the second bit line BL2 in the third direction D3. The first bit line BL1 may overlap with the first to third memory channel structures CS1, CS2 and CS3, the dummy channel structure DCS, the first separation structure 151 and the second separation structure 152 in the third direction D3. The first bit line BL1 may include a conductive material.

The third contact CT3 may be connected to a corresponding one of the second contacts CT2. A lower portion of the third contact CT3 may be located at the same level as the first bit line BL1. The third contact CT3 may be located at the same level as the bypass structure BP. A top surface of the third contact CT3 may be coplanar with a top surface of the bypass structure BP. The third contact CT3 may overlap with the third bit line BL3 and the second contact CT2 in the third direction D3. The third contact CT3 may be electrically connected to the third memory channel structure CS3. The third contact CT3 may include a conductive material.

The bypass structure BP may include a first portion P1 and a second portion P2 on the first portion P1. A width of the second portion P2 of the bypass structure BP may be greater than a width of the first portion P1 of the bypass structure BP (see, e.g., FIG. 2C). For example, a width W2, in the second direction D2, of the second portion P2 of the bypass structure BP may be greater than a width W1, in the second direction D2, of the first portion P1 of the bypass structure BP.

The first portion P1 of the bypass structure BP may be connected to a corresponding one of the second contacts CT2. At least a portion of the first portion P1 of the bypass structure BP may be located at the same level as the first bit line BL1. For example, a lower portion of the first portion P1 of the bypass structure BP may be located at the same level as the first bit line BL1. The second portion P2 of the bypass structure BP may be located at a higher level than the first bit line BL1. A bottom surface of the second portion P2 of the bypass structure BP may face a top surface of the first bit line BL1.

A top surface of the second portion P2 of the bypass structure BP may be coplanar with a top surface of the third contact CT3. The first portion P1 of the bypass structure BP may overlap with the second contact CT2 in the third direction D3. The second portion P2 of the bypass structure BP may include a portion overlapping with the first bit line BL1, the second bit line BL2 and the fourth contact CT4 in the third direction D3, and a portion overlapping with the second contact CT2, the first portion P1 of the bypass structure BP and the third bit line BL3 in the third direction D3.

The second portion P2 of the bypass structure BP may be connected to the fourth contact CT4. The bypass structure BP may be electrically connected to the second bit line BL2 and the second memory channel structure CS2. The bypass structure BP may include a conductive material.

The fourth contact CT4 may be connected to the second portion P2 of the bypass structure BP. The fourth contact CT4 may overlap with the second bit line BL2, the first bit line BL1 and the second portion P2 of the bypass structure BP in the third direction D3. The fourth contact CT4 may be electrically connected to the second memory channel structure CS2. The fourth contact CT4 may include a conductive material.

The fifth contact CT5 may be connected to the third contact CT3. The fifth contact CT5 may be located at the same level as the fourth contact CT4. A top surface of the fifth contact CT5 may be coplanar with a top surface of the fourth contact CT4. The fifth contact CT5 may overlap with the third bit line BL3, the third contact CT3 and the second contact CT2 in the third direction D3. The fifth contact CT5 may be electrically connected to the third memory channel structure CS3. The fifth contact CT5 may include a conductive material.

The second bit line BL2 may be electrically connected to the second memory channel structure CS2 through the fourth contact CT4, the bypass structure BP, the corresponding second contact CT2 and a corresponding stud contact 221. The second bit line BL2 may be electrically isolated from the first memory channel structure CS1 and the third memory channel structure CS3. The second bit line BL2 may overlap with the first bit line BL1 in the third direction D3. The second bit line BL2 may overlap with the first to third memory channel structures CS1, CS2 and CS3, the dummy channel structure DCS, the first separation structure 151 and the second separation structure 152 in the third direction D3. The second bit line BL2 may include a conductive material.

The third bit line BL3 may be electrically connected to the third memory channel structure CS3 through the fifth contact CT5, the third contact CT3, the corresponding second contact CT2 and a corresponding stud contact 221. The third bit line BL3 may be electrically isolated from the first memory channel structure CS1 and the second memory channel structure CS2. The third bit line BL3 may overlap with the first to third memory channel structures CS1, CS2 and CS3, the dummy channel structure DCS, the first separation structure 151 and the second separation structure 152 in the third direction D3. The third bit line BL3 may include a conductive material.

However, embodiments are not limited to the illustrated arrangement of a first channel connection structure including the first memory channel structure CS1, the stud contact 221 and the first contact CT1 which are connected to each other, a second channel connection structure including the second memory channel structure CS2, the stud contact 221, the second contact CT2, the bypass structure BP and the fourth contact CT4 which are connected to each other, and a third channel connection structure including the third memory channel structure CS3, the stud contact 221, the second contact CT2, the third contact CT3 and the fifth contact CT5 which are connected to each other. In some embodiments, the third channel connection structure may be farthest from the dummy channel structure DCS, and the first channel connection structure may be closest to the dummy channel structure DCS. In some embodiments, the third channel connection structure may be farthest from the dummy channel structure DCS, and the second channel connection structure may be closest to the dummy channel structure DCS. In some embodiments, the first channel connection structure may be farthest from the dummy channel structure DCS, and the second channel connection structure may be closest to the dummy channel structure DCS. In some embodiments, the second channel connection structure may be farthest from the dummy channel structure DCS, and the third channel connection structure may be closest to the dummy channel structure DCS. In some embodiments, the second channel connection structure may be farthest from the dummy channel structure DCS, and the first channel connection structure may be closest to the dummy channel structure DCS.

Since the semiconductor device according to the embodiments described above includes the first and second bit lines BL1 and BL2 overlapping with each other and the bypass structure BP, a density of the memory channel structures CS1, CS2 and CS3 between the first and second separation structures 151 and 152 adjacent to each other may relatively increase, and an integration density of the semiconductor device may be improved.

FIG. 3A is a plan view illustrating a semiconductor device according to some embodiments. FIG. 3B is an enlarged view of a region ‘B2’ of FIG. 3A. FIG. 3C is an enlarged view of a region ‘B3’ of FIG. 3A. FIG. 3D is a cross-sectional view taken along lines C2-C2′, D2-D2′, E2-E2′ and F2-F2′ of FIGS. 3B and 3C.

Referring to FIGS. 3A, 3B, 3C and 3D, a semiconductor device may include a gate stack structure GSTa, first memory channel structures CS1a, second memory channel structures CS2a, third memory channel structures CS3a, fourth memory channel structures CS4a, dummy channel structures DCSa, a connection structure 200a, a first separation structure 151a, and a second separation structure 152a.

The gate stack structure GSTa may include insulating patterns IPa and conductive patterns CPa. The first and second separation structures 151a and 152a may extend in the third direction D3 to penetrate the gate stack structure GSTa. The first and second separation structures 151a and 152a may be separation structures adjacent to each other.

The first memory channel structures CS1a, the second memory channel structures CS2a, the third memory channel structures CS3a, the fourth memory channel structures CS4a and the dummy channel structures DCSa may be disposed between the first separation structure 151a and the second separation structure 152a.

The connection structure 200a may include a first insulating layer 201a, a second insulating layer 203a on the first insulating layer 201a, a third insulating layer 205a on the second insulating layer 203a, a fourth insulating layer 207a on the third insulating layer 205a, a fifth insulating layer 209a on the fourth insulating layer 207a, a sixth insulating layer 211a on the fifth insulating layer 209a, a seventh insulating layer 213a on the sixth insulating layer 211a, an eighth insulating layer 215a on the seventh insulating layer 213a, a ninth insulating layer 217a on the eighth insulating layer 215a, a tenth insulating layer 219a on the ninth insulating layer 217a, stud contacts 221a penetrating the first and second insulating layers 201a and 203a, first contacts CT1a and second contacts CT2a which penetrate the third insulating layer 205a, first bit lines BL1a in the fourth insulating layer 207a, third contacts CT3a and first bypass structures BP1a which penetrate the fourth and fifth insulating layers 207a and 209a, fourth contacts CT4a and fifth contacts CT5a which penetrate the sixth insulating layer 211a, second bit lines BL2a in the seventh insulating layer 213a, sixth contacts CT6a and second bypass structures BP2a which penetrate the seventh and eighth insulating layers 213a and 215a, seventh contacts CT7a and eighth contacts CT8a which penetrate the ninth insulating layer 217a, and third bit lines BL3a and fourth bit lines BL4a in the tenth insulating layer 219a. The first to fourth bit lines BL1a, BL2a, BL3a and BL4a may overlap with each of the memory channel structure CS1a, CS2a, CS3a and CS4a in the third direction D3. Each of the first bit line BL1a, the second bit line BL2a, the third bit line BL3a and the fourth bit line BL4a may overlap with the first to fourth memory channel structures CS1a, CS2a, CS3a and CS4a, arranged in the first direction D1, in the third direction D3.

The stud contacts 221a may be connected to the first to fourth memory channel structures CS1a, CS2a, CS3a and CS4a, respectively.

The first bit line BL1a may be electrically connected to the first memory channel structure CS1a through the first contact CT1a and a corresponding one of the stud contacts 221a. The second bit line BL2a may be electrically connected to the second memory channel structure CS2a through the fourth contact CT4a, the first bypass structure BP1a, a corresponding one of the second contacts CT2a and a corresponding one of the stud contacts 221a. The fourth bit line BL4a may be electrically connected to the fourth memory channel structure CS4a through the eighth contact CT8a, the sixth contact CT6a, a corresponding one of the fifth contacts CT5a, a corresponding one of the third contacts CT3a, a corresponding one of the second contacts CT2a and a corresponding one of the stud contacts 221a. The third bit line BL3a may be electrically connected to the third memory channel structure CS3a through the seventh contact CT7a, the second bypass structure BP2a, a corresponding one of the fifth contacts CT5a, a corresponding one of the third contacts CT3a, a corresponding one of the second contacts CT2a and a corresponding one of the stud contacts 221a.

The first bypass structure BP1a may include a first portion Pla and a second portion P2a having a width greater than that of the first portion Pla. The second bypass structure BP2a may include a first portion P3a and a second portion P4a having a width greater than that of the first portion P3a.

The first to third bit lines BL1a, BL2a and BL3a may overlap with each other in the third direction D3. The second portion P2a of the first bypass structure BPla may overlap with the first to fourth bit lines BL1a, BL2a, BL3a and BL4a in the third direction D3. The second portion P4a of the second bypass structure BP2a may overlap with the first to third bit lines BL1a, BL2a and BL3a in the third direction D3. The first portion Pla of the first bypass structure BP1a may overlap with the fourth bit line BL4a. The first portion P3a of the second bypass structure BP2a may overlap with the fourth bit line BL4a.

The second bit line BL2a may be located at a higher level than the first bit line BL1a. The third and fourth bit lines BL3a and BL4a may be located at a higher level than the second bit line BL2a. The second portion P2a of the first bypass structure BP1a may be located at a higher level than the first bit line BL1a and may be located at a lower level than the second bit line BL2a. The second portion P4a of the second bypass structure BP2a may be located at a higher level than the second bit line BL2a and may be located at a lower level than the third and fourth bit lines BL3a and BL4a.

However, embodiments are not limited to the illustrated arrangement of a first channel connection structure including the first memory channel structure CS1a, the stud contact 221a and the first contact CT1a which are connected to each other, a second channel connection structure including the second memory channel structure CS2a, the stud contact 221a, the second contact CT2a, the first bypass structure BP1a and the fourth contact CT4a which are connected to each other, a third channel connection structure including the third memory channel structure CS3a, the stud contact 221a, the second contact CT2a, the third contact CT3a, the fifth contact CT5a, the second bypass structure BP2a and the seventh contact CT7a which are connected to each other, and a fourth channel connection structure including the fourth memory channel structure CS4a, the stud contact 221a, the second contact CT2a, the third contact CT3a, the fifth contact CT5a, the sixth contact CT6a and the eighth contact CT8a which are connected to each other. In some embodiments, the first channel connection structure may be closest to the dummy channel structure DCSa, and the fourth channel connection structure may be farthest from the dummy channel structure DCSa.

FIG. 4A is a plan view illustrating a semiconductor device according to some embodiments. FIG. 4B is a cross-sectional view taken along lines C3-C3′, D3-D3′ and E3-E3′ of FIG. 4A.

Referring to FIGS. 4A and 4B, a semiconductor device may include a gate stack structure GSTb, first memory channel structures CS1b, second memory channel structures CS2b, third memory channel structures CS3b, dummy channel structures DCSb, a connection structure 200b, a first separation structure 151b, and a second separation structure 152b.

The gate stack structure GSTb may include insulating patterns IPb and conductive patterns CPb. The first and second separation structures 151b and 152b may extend in the third direction D3 to penetrate the gate stack structure GSTb. The first and second separation structures 151b and 152b may be separation structures adjacent to each other.

The first memory channel structures CS1b, the second memory channel structures CS2b, the third memory channel structures CS3b and the dummy channel structures DCSb may be disposed between the first separation structure 151b and the second separation structure 152b.

The connection structure 200b may include a first insulating layer 201b, a second insulating layer 203b on the first insulating layer 201b, a third insulating layer 205b on the second insulating layer 203b, a fourth insulating layer 207b on the third insulating layer 205b, stud contacts 221b penetrating the first and second insulating layers 201b and 203b, first, second and third contacts CT1b, CT2b and CT3b penetrating the third insulating layer 205b, and first, second and third bit lines BL1b, BL2b and BL3b in the fourth insulating layer 207b. The first to third bit lines BL1b, BL2b and BL3b may overlap with each of the memory channel structure CS